Open for lunch from noon to 2:30 p.m. Monday through Friday; dinner seven days a week from 6 to 10:30 p.m. Reservations encouraged. Valet parking. AE, DC, CB, V, MC. Prices: For lunch appetizers from $4.25 to $7.50, entrees from $13.75 to $18.50; for dinner appetizers from $4.25 to $12, entrees from $16.50 to $23.50. Diner with wine, tax and tip about $50 to $60 a person.

Hotels are trying to catch up. not only is there a boom in building them in Washington, and in refurbishing them, but they are upgrading their dining rooms and trying tocompete for the luxury dollar by installing small, lush restaurants that showcase a talented chef. The most impressive of the new hotel restaurants has been the Mayfair in the Regent hotel, but its outstanding young German chef has left. And now the Mayflower hotel has entered the arena, with a restaurant not quite so ambitious or stratospherically priced as the Mayfair, and this time with an emphasis on new American rather than new European food.

It is called Nicholas, after the Mayflower's first executive chef. Its menu is full of fashionable ingredients -- red bell peppers, green peppercorns, raspberry vinegar, enoki mushrooms, coriander and ginger -- in inventive dishes that combine flavors of Europe and Asia with America's best resources: crab meat, swordfish, Maine lobster, red snapper, Wisconsin duck, rack of lamb, filet of beef. This is no tired menu of sole veronique and steak diane.

The appetizers are beautifully garnished with tomato roses and dabs of caviar, or with tiny pickled vegetables or tropical fruits. Among them are marinated salmon and scallops with green peppercorns and lime or tuna tartare with chives and dill. Both are nice, though the tuna tartare is the more satisfactory. The scallop-stuffed ravioli have paper-thin pasta skin, weighty with scallop pieces; they are served in red pepper beurre blanc and on a bed of spinach that improve them further. Nearly as extravagant and also delicious is the lobster in a delicate butter and vermouth sauce. Of the two duck appetizers -- a duck terrine and sauteed foie gras -- the foie gras is delicious, with a coriander sauce that does not overwhelm the duck livers. The duck terrine, however, was the only disappointing appetizer, damp and strong-tasting.

But dinner starts even before the appetizers. First, the waiter whisks the napkin from its silver ring and covers your lap with it; then he brings a tiny hors d'oeuvre, such as cheese-filled phyllo triangles, for you to enjoy as you examine the menu. Then the warm and crusty bread arrives; the waiter pours Mountain Valley water into long-stemmed glasses, and soft baroque music plays in the background (though the tape becomes repetitive over a long evening).

The scene is set for a special meal.

The rooms are small, decorated with pale colors, traditional paintings and crystal chandeliers and sconces. But the table-tops are handsome with silver, heavy white linen, silk-shaded lamps and gorgeous service plates. An awkward bonsai arrangement on one wall has been replaced with masses of flowers -- a definite improvement. Another improvement will be when the waiters become less nervous and sound less rehearsed, for the mechanics of the service are conscientious.

Nicholas is proud of its wine list, which concentrates on California, and indeed it is a good representation of America's top wines. But the prices are high, and it is a challenge to find something worthy to drink under $20 (the Guenoc Petite Syrah was the best I could find).

The soups suggest that this is a menu that is not routine. A cream of grilled eggplants with bell pepper and sesame is a haunting, unexpected taste, though it retained the bitterness of old eggplant. Pheasant consomme with orange, ginger and tomato was sparked nicely with its ginger and orange but was overpowered by alcohol.

There are not always daily specials, but when there are, you should Carole Sugarman

pay them heed. One night there was an excellent nearly boneless, flattened and crisp-skinned pigeon that was impeccable, and the blackened redfish -- the fish dish of the season in this country -- was an excellent job (if not quite as good as the New Orleans Emporium's), quite heavily coated with spices, well charred and served on a bed of relish.

Unlike many restaurants, where inconsistency is from dish to dish, at Nicholas I found the inconsistency to be greater from night to night. One evening main dishes were off: the lamb was overcooked and grainy, its artichoke slices flavorless, though its tarragon sauce was decent. Duck breast was just ordinary, cooked past pink and with a cabernet sauce that was merely pleasant. Lobster with dill and cucumbers was the best dish that night, prettily shelled and reformed, on a pool of buttery dill sauce. But all the food lacked personality. Another night the chef was in letter form. That blackened redfish was excellent, the pigeon delicious. And a poached salmon topped with a bouquet of enoki mushrooms wrapped in a green stem was delectable, its buttery sauce livened with shreds of green; and even those ordinarily bland hair-thin mushrooms had considerable flavor. The vegetables were similarly excellent on both nights -- a lovely display of piped sweet potatoes sprinkled with nuts, snow peas, peeled cherry tomatoes and batons of squash, plus utterly delicious spinach leaves. The sweet potatoes' taste inspired. And even on the lesser of the evenings, the sauces were admirably light and delicately applied.

Nicholas is a restaurant that impresses more in the whole than for any particular quality. The desserts, though, are among its greatest assets. Remember to order a souffle early in the evening: it is light and airy, with a sugary crustiness and a clear flavor of maple syrup and restrained tinge of bourbon. But you will certainly want to try the brioche bread pudding, buttery and crunchy, its top as puffed as a souffle; or there might be a rich and crunchy creme brulee with strawberries, or meringue, flat and round and covered with rings of marinated strawberries intriguingly perfumed with black pepper. Chocolate mousse on pistachio cream? It's good, but it takes a back seat to the other desserts. Or you could just wait for the ending: a tray of marvelous pecan squares, chocolate kisses and cookies, though they were offered to us only once. And you casn brace for a winter evening with strong brewed coffee, decaffeinated or regular.

Nicholas is a series of thoughtful and attractive, touches on a base of good cooking and imagination. It raises the standards of hotel dining in Washington, for there are few hotels that match it. It brings another new American chef to the small ranks of that genre in this city. It is off to a good start.